In this guide I’ll show you how to squeeze out more juice out of your Geforce 8 and 9 series video cards but before all a warning is due.
All the images here are from a Geforce 8800 GT but its all the same for Geforce 9 cards
Warning!
The procedures that are shown here are not for novice users. Overclocking, flashing the Video card bios, will void any warranties you have for the product (some manufacturers provide warranties for cards failed by over clocking like EVGA, but remember if u tamper with the video Bios your warranty will go haywire) and also may render your graphic cart useless, may reduce its life span and can also harm other parts of your system (in the event of overheating). You follow the procedures mentioned in this article at your own risk; I am not responsible if you ruin your Graphic card by following this guide.
Ok now you got pretty scared, but don’t be, because it’s a very safe thing to do if you do it the right way.rst, the tools and hardware you will need as follows;
- Rivatuner (version 2.09 is the latest build while writing this guide)
- GPU-Z (another handy utility but no used much in this guide)
- NiBiTor (nVidia Bios Editor) version 3.8
- Nvflash (nVidia firmware updating utility)
- Graphics intensive game or 3dmark 2006 (for stress testing)
- Bootable floppy disk (foor flashing the video bios)
- Old PCI video card (this for recovering you graphic card if something go wrong, I’ll show you how to do it later in the guide)
Geforce 8 s GPU (and all direct X 10 cards) is very different from the GPU’s of the previous generation of graphics processors, it features something called unified shaders, and (you might know that all previous GPU’s had Pixel shaders and Vertex shaders that work independently to process pixel shading and vertices) unified shaders can both work as pixel shaders and vetex shaders at the same time, for an example if a game need a lot of pixel shading power the GPU can allocate more unified shaders to that and less for vertex shading, any way the whole point of me telling you this is that these new cores have the ability independently change the core clock of the GPU and the clock of the shaders (shaders are a bunch of stream processors).
Principles of overclocking a video card
As I have told you earlier these new Geforce cards features two clock domains to overclock the GPU (these two are generally linked, means if you OC the core clock by 10% then the Shader clock also increase by 10%, but this can be unlinked in Rivatuner though it is not recommended), beside that, as you might know you can overclock the graphics memory also, it is not recommended that you overclock all of these at once, the best practice is to over clock step by step, first you have to find the limits of the GPU and then default the GPU’s clock and go to work with the memory, this way you can avoid complicated situations.
Overclocking using RivaTuner
This is the tool I prefer to use all the time, but you can use any one of those good tools out there, RivaTuner is an Advanced Graphic Card tweaking utility capable of plethora of tasks including overclocking.
First start of Rivatuner
Riva Tuner main window
1 - Click this button to open the Customization Menu
2 - Click the Graphic Card Icon to bring up the System Tweaks window thats where we do our work most of the time
First you have to Enable Driver Level overclocking, to do that click on the check box, a message box will popup if you want to reboot to detect default clock speeds of the card, if haven’t done any over clocking before, you may click the detect now button or else click restart button so the card will reset to default values upon system reboot.
Before starting to OC...Always check that you have proper cooling and if your card has the ability control the cooling fan speed, set it to 100% to make sure maximum cooling is applied, Always keep an eye on the temps while ur overclocking, dont let them go beyond 100C
Now we can get on with the business of overclocking, we'll start off with the core clock, don’t tamper with the shader clock and don’t unlink it with the core clock let the memory speed on default, increase the core clock in 10Mhz increments, after each increment stress your card with either 3dmark 2006 or some very graphic intensive game like Crysis, while you’re doing this pay very careful attention to what you see on the screen, if you see any texture corruption or screen blackout, system Restart, Hanging, your pushing too hard on the core clock so reduce it by 10Mhz, repeat this procedure until you find a stable frequency for the core clock.
Now reset the Core clock to default values by clicking on the Default button (this actually reset the whole card to factory defaults).
After finishing with the core clock we shall now move on to memory clock (remember memory is very sensitive to heat and you will need good cooling to OC memory) it’s always safe to increase the memory 5Mhz at a time, even though good memory can be directly over clocked without any damage, to be on the safe side follow the 5Mhz at a time rule, as with the core clock stress test after each increment and find the most stable frequency for the memory.
Now you can set the new found core clock and the memory clock at the same time, do another stress test just to make sure it is all stable, save the new OC profile using the save button. That’s it guys. (now most of you will get satisfied with this simple procedure, you’ll have to load the OC profile each time you reboot you’re PC, if this is not a hassle for you then you are all done, if you are really a speed freak like me
, please continue reading) Advanced Bios overclocking
If you don’t know what you are doing please don’t attempt any of the following procedures
As you might know Video Cards have a Bios that have information of the default clock speeds, fan speeds, voltages and so on, these settings are loaded on the System POST (Remember the Text appear first stating the Make and the Manufacturer of the card), now if you are like me, who don’t like to load OC profiles In windows each time you start your system, you need to change them in the Video bios, lets proceed shall we
To do this you need Nibitor and nvflash
Nvidia Bios Editor is a Advanced Nvidia Bios editing utility combined with Nvflash (nvidia bios flash utility), that can, I must stress this “Kill” your graphic card if you use it the wrong way.
Before anything else, you must first take a clean bios image of your graphic card and keep it somewhere safe; you will need this if you mess things up
Fire up Nibitor
Click on the tools menu got to import bios sub menu and click select device, a window will popup asking you to select your video card, click ok, now the main window will populate with the settings from the bios, to save the bios to a file, click on the file menu and select save bios, give a location and you are done.
Now to set up the boot up clock speeds of the video cards, since you now have stable overclocked frequencies at hand it’s the time to use them here.
As you might have noticed the default clocks of your card is already shown on the main window, now we have to change them to our new and improved lol clocks, click the bootup clocks button.
now change the appropriate Core, Shader and memory clocks with the new Values and hit ok button.
Now to make your video cards post screen more attractive hehe, click on the boot settings tab
in here you can change the Post text as I have changed on this screen shot lol, mess arround with this section cuz its quite safe.
Do not try to change any settings other than the ones i have told you earlier if you don’t know what you are doing, leave them as they are.
After finishing all this, now it’s the time to save the modified bios to a new file, go to the file menu and select save bios and give a path, and you are done.
Now we move on to the quite dangerous method of flashing the video bios.
Get the Nvflash utility and put it and the new bios image (let’s say this new bios image is named ocbios.rom) to the bootable floppy disk, stick it inside the floppy drive and boot up, after booting to the DOS prompt, type “nvflash -p -u -f ocbios.rom” without the quotes, then the bios will be flashed to the Video Cards EPROM, restart the pc after this, if all went well you will boot up to windows, and will be happy as you can be, but if you find that your newly flashed bios is giving you trouble you can re flash it with the original bios you saved earlier (let’s say its named originalbios.rom) to do this type “nvflash -p -u -f originalbios.rom”, Congradz you have successfully over clocked and flashed your new Geforce 8.
now if you really screwd things up you might be looking at a blank screen during post, if so please read on.
This is where you will need the old PCI video card, stick it in, remove the PCI-e card, boot up and go to bios, in bios find a setting that set the default VGA to either PCI or PCI-e, set it to boot from PCI, turn the system off, now you can stick the PCI-e card in and still boot from the PCI card, now re flash the PCI-e card properly with the original bios and hopefully it’ll start working again.
Remember that this kind of situation happens quite rarely if you do the things right and if you know what you are doing so don’t chicken out, experiment and the rewards will be there.
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